Shank-stiffener.



PATENT@ JULY' 23, 15907. G.P..DUNN. A

SHAN'K STFFENER.

APPLIDATION FILED HELM, 1905.

UNITEn sfrafr ns ,'Pa'rnnr onirica GlUlttl},l DUNN, OF BROGKTON, MASSACHUSETTS', ASltiNUlt i'U WILLIAM B. RNOLD,

OI NORTH ABINGTON,a MASSACHUSETTS.

SHANK-STIFFENER.

' Specification of Letters Patent.

y rasanten July 23, 1907.

Application filed January 24,1905. vSerial No. 242,487.

To all whom 'it may concern:

Be it known that I, GEORGBF. DUNN, a citizen of the United States, residing at Brockton, in the county of Plymouth and State of Massachusetts, have invented an Improvement in Shaiik-Stifieners, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My invention is an improved shank stiffener having for yits object the provision of means or insuring the permanence of the arch at the shank of the boot or shoe, with material light in weight, and extremely neat appearance'.

One of the common forms of shank stifiener is a strip of sheet steel, originally flat, which .is bent to the shape o the arch required, but this requires an undue weight and thickness of material as well as high grade steel, and accordingly another form of shank has been ernployed consisting of two thinner pieces of metal arched with slightly different curves and fastened to each other at their ends, but this also is heavy, expensive -and cumbersome. I have found that I can meet the requirements of light weight, thin material, slight cost, and the avoidance of creases and ridges in the inelosing leather ot' the shank, by providing a thin steel or similar stiff metal shank'arched properly and provided along its middle with a longitudinal 'curve arched upwardly so that the stilfener has its greatest length along its lon gitudinal center which is also the highest portion of the stifiener, the metal depending slightly from said central portion toward theopposite edges of the stilener which are curved back upwardly more or less'sharply for the greater portionol' the length pl the stil'icner. A

MA invention will be further understood from the following description taken in connection with the ac coiupanying drawings.

ln said drawings, Figure l is a lop plan view ot" my improved shank stifl'fmcr, Fig. 2 is a View thereof in side elevation partly broken away for clearly illustrating the construction; and Fig. Zl'is a transverse sectional View taken ou the liml 3-3 Fig. l.

'lhe shank s tifr-.ner a is prelerably made ol' thin steel having proper thickness and temper for the rough. usage and cuntiluuius work required of it. lhe opposite ends u are flat or plano and preferably perforated in usual manner al, o'r'. .lust behind these perlorations the metal is upwardly bont longitudinally along its central portion :1s indicated at a and thence the metal strip depends at the opposite sides u" ol said central longitudinal upward vuurwl'frd the edges. 'lhe metal is thence curved bin-ller upwardly al. its edges as 'iudi cal/ed at l' to about' the height ol' the central upward longitudinal curve, the edge curve, however, boing 'quite sharp and short, while the central upward curve tharply bent-up ledges a5 is gradual and broad as clearly shown in Fig. 3. '-This improved shank stiffener is arched from end to end, as shown in Fig. 2, to correspond to the hollow of the foot and the shank of the shoe, being stamped or struck up with all its curvatures and arching simultaneously .so that the metal is expanded or stretched in the process of formation In use, I have found that a shank stiffener thus formed may be very thin and light. It is inserted and secured in the shank of a boot or shoein' the same man-- ner as heretofore, and yet, notwithstanding the fact that it has a longitudinal hollow or slight depression extending centrally along its under side, the upwardly curved edges and thin light construction prevent the formation of any noticeable creases or central ridge along the longitudinal middle of the boot or shoe shank.

The particular construction which I provide stretches the metal as already stated, and produces a construction inwhich the outside layer of leather presses the into the inside 'layer of leather at such an angle that it is practically impossible for the shank to break down or give out under ordinary lwalking strains. The shank is not merely reinforced and strengthened because ol' its being bent as would be the ease with a piece of corrugated metal, but the particular location and arrar gement of the bends, the outer upward bend being sharp or abrupt and the inner bend being gradual, the outer bend being short, and the inner bend being long, and the inner bend being formed simultaneously with the formation of the entire shank and not extending to the ends, whereby said formation produces a stretching and expanding of the metal, all conduce, in connection with the upper and lower layersof leather-which embracethe shank above-and below, to produce the advantageous results described.

IfIaving described my invention, what I claim as new, and desire to secure by Letters Patent of the United States, isz- 4 As an article of manufacture, a shank stltl'ener, consisting of n thin metal strip having fiat ends and arched ,thence from one of said flat ends -to the other to conform lto the shank of u boot or shoe) the intermediate portion of the stft'ener between the sides and ends having the metal stretched and expanded upwardly lin a broad, low, longitudinal bulge or upward bend, highest along the longitudine-.l center. ol' the. stiltener und converging luto the plane sur tures nl' the ends thereof, said stltener at lts slde edges hnvin;r short. upward bends extending' to approximately the, height ol' said longitudinal bulge or bend for engaging approximately perpendicular-ly the adjacent surface of the Inner layer o leather :it their extreme edges.

ln testimony whereof, I have spccllleutlon, ln the presence of two subscribing wltnesses.

l GEORGE F. DUNN.

Witnesses (l1-io. 1I. Mnkwnf' M. A. Joni-ss.

signed my naine to this 

